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Researchers from MIT Concrete Sustainability Hub (CSHub) are working in collaboration with the French National Center for Scientific Research (CNRS) towards making concrete more sustainable. They plan to do so by electrifying concrete, which would allow its application for several new purposes, ranging from energy storage to self-heating.
Their approach relies on the controlled addition of highly conductive nanocarbon materials to the cement mixture. In a paper titled Physical Review Materials, they corroborate this approach while depicting the parameters that govern the conductivity of the material.
By introducing nanocarbon black at just a 4% volume of their mixtures, the researchers found that they could reach the percolation threshold, which is the point at which their samples could carry current.
There is an interesting upshot to this experiment, as the researchers observed that their samples could also generate heat. This is due to the Joule effect, which is caused by the interaction between the moving electrons and atoms in the conductor.
In their attempts, they found that even a small voltage (as low as 5 V) could raise the surface temperatures of their samples (approximately 5 cm3 in size) up to 41°C (around 100°F). While a standard water heater might reach similar temperatures, it’s important to consider how this material would be implemented in contrast to conventional heating systems.
This development could prove to be ideal for radiant indoor floor heating. Presently, the heating system involves the circulation of hot water through the pipes beneath the floor levels, which can be challenging to install and maintain.
When the construction material itself becomes a heating element, the heating system would be simpler to install and more reliable. Also, the concrete offers more homogenous heat distribution due to the uniform dispersion of the nanoparticles in the material.
The material could have various outdoor applications, such as in concrete pavements, where it would be possible to de-ice pavements without road salt, helping save millions of dollars in maintenance and operations costs while mitigating safety, durability, and environmental concerns.